Effects of Tall Buildings on Urban Airflow and Pollution

Background: Air pollution in cities is influenced by wind speed and direction, which are shaped by urban fabric elements like building density, green spaces, and land use. Tall buildings, increasingly common in modern cities, disrupt wind flow and exacerbate pollutant concentration, posing challenges for urban planners responsible for designing sustainable urban layouts. Methods: This study analyzed the effects of building height on pollutant dispersion in southwest Tehran (Region 18) using computational fluid dynamics (CFD) simulations and geographic information systems (GIS). A pollution distribution map was developed in GIS, while wind speed data were simulated in Autodesk software and validated. The study examined how altering building heights impacts wind flow and pollutant concentration. Results: Findings showed significant variations in wind speed and pollutant levels based on the urban layout. In areas with fewer obstacles, wind speed increased, reducing pollutant concentrations through enhanced dispersion. Conversely, dense and tall buildings reduced wind speed, leading to pollutant accumulation. The results highlight that building height and arrangement substantially influence wind patterns and air quality. Conclusion: The study underscores the critical role of urban design in air quality management. By increasing wind flow, pollutant dilution can be enhanced, mitigating health risks. Urban planners must prioritize layouts that support natural ventilation and consider the impact of tall buildings on pollutant dispersion to promote healthier urban environments.